# Subdomain Finder — Passive Subdomain Enumeration (Subfinder) (`ntriqpro/subfinder-osint`) Actor

Discover subdomains of any domain fast using the open-source Subfinder engine — passive enumeration from dozens of public sources (certificate transparency, DNS datasets, search engines). For attack-surface mapping and authorized security research.

- **URL**: https://apify.com/ntriqpro/subfinder-osint.md
- **Developed by:** [daehwan kim](https://apify.com/ntriqpro) (community)
- **Categories:** Developer tools, Business
- **Stats:** 2 total users, 2 monthly users, 100.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

$10.00 / 1,000 subdomain founds

This Actor is paid per event. You are not charged for the Apify platform usage, but only a fixed price for specific events.

Learn more: https://docs.apify.com/platform/actors/running/actors-in-store#pay-per-event

## What's an Apify Actor?

Actors are web data automations that power AI and operations. They run on the Apify platform to scrape websites, process data, connect APIs, and automate workflows.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.
Actors are written with capital "A".

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.
The best way to integrate Actors is as follows.

- **AI agents and MCP clients** — the [Apify MCP server](https://docs.apify.com/integrations/mcp.md) at `https://mcp.apify.com` (remote, streamable HTTP, OAuth on first use).
- **Agentic workflows and local Actor development** — [Agent Skills](https://apify.com/.well-known/agent-skills/index.json) with the [Apify CLI](https://docs.apify.com/cli/docs.md): `npm install -g apify-cli`, then `apify login`.
- **JavaScript/TypeScript projects** — the official [JS/TS client](https://docs.apify.com/api/client/js/docs.md): `npm install apify-client`.
- **Python projects** — the official [Python client](https://docs.apify.com/api/client/python/docs.md): `pip install apify-client`.
- **Any other language** — the [REST API](https://docs.apify.com/api/v2.md).

For usage examples, see the [API](#api) section below.

For more details, see Apify documentation as [Markdown index](https://docs.apify.com/llms.txt) and [Markdown full-text](https://docs.apify.com/llms-full.txt).

# README

## Subdomain Finder — Passive Subdomain Enumeration (Subfinder)

Discover **all the subdomains of any domain**, fast, using [Subfinder](https://github.com/projectdiscovery/subfinder) (MIT) — the industry-standard passive subdomain enumeration engine by ProjectDiscovery. It pulls subdomains from **dozens of public sources** (certificate transparency logs, DNS datasets, search engines, threat-intel feeds) — no brute force, no port scanning, just fast passive discovery.

Built for **security researchers, bug-bounty hunters, pentesters, and attack-surface-management teams** who need to map a domain's footprint in seconds.

> **Legal notice:** This Actor is an unofficial integration of subfinder (projectdiscovery/subfinder) and is not affiliated with or endorsed by ProjectDiscovery. It uses **public passive data only**. Enumerate only domains you own or are authorized to assess, and comply with all applicable laws.

### What does this Actor do?

Give it a domain (e.g. `example.com`) and it returns every subdomain it can find from public passive sources — `api.example.com`, `mail.example.com`, `staging.example.com`, and so on — each with the source that surfaced it. Running on Apify adds scheduling, a REST API, dataset exports (JSON/CSV/Excel), and monitoring, so you can track a domain's growing attack surface over time.

### Why use this Actor?

- **Attack-surface mapping** — see every public-facing subdomain an organization exposes.
- **Bug bounty / pentest recon** — the fastest first step of any engagement.
- **Shadow-IT discovery** — find forgotten staging, dev, and legacy hosts.
- **Continuous monitoring** — schedule scans and diff results to catch newly created subdomains.

### How to use it

1. Enter a **domain** (`example.com` — no `http://`, no path).
2. Run it. Each unique subdomain becomes one dataset row.
3. Export to CSV/JSON/Excel or pull via the API. Schedule for ongoing monitoring.

### Input

| Field | Type | Description |
|---|---|---|
| `domain` | string | Root domain to enumerate, e.g. `example.com`. **Required.** |
| `maxResults` | integer | Cap on subdomains returned/charged (default 500, max 2000). |
| `timeout` | integer | Max seconds for enumeration (default 180). |

### Output

Each unique subdomain is one dataset record. Download as JSON, HTML, CSV, or Excel.

```json
{
  "domain": "example.com",
  "subdomain": "api.example.com",
  "source": "crtsh",
  "scannedAt": "2026-06-29T00:00:00+00:00"
}
```

### Pricing / Cost estimation

**Pay-per-result: $0.01 per unique subdomain discovered.** A small site may return a handful of subdomains (a few cents); a large organization can return hundreds — use `maxResults` to cap your spend. No subdomains found = no charge. New Apify users get free monthly credits.

### Tips & advanced options

- Use `maxResults` to control cost on large targets.
- Schedule weekly runs and diff the output to catch **newly created** subdomains (often staging/dev hosts that leak early).
- Pair with our **dnstwist** Actor (look-alike domains) and **theHarvester** Actor (emails/hosts) for full external recon.

### FAQ, disclaimers & support

**Is this legal?** It performs **passive** enumeration from public data sources only — no brute force, no scanning of the target's servers. Use it for attack-surface mapping of domains you own or are authorized to assess.

**Known limitations:** Passive sources have coverage gaps; some sources return more results with their own API keys. Very large targets may hit the timeout (raise `timeout` or lower `maxResults`).

- Found a bug or need a custom recon solution? Open an issue in the **Issues** tab.

***

### 🔗 Related Actors by ntriqpro

Build your full recon & OSINT stack:

- [**theharvester-osint**](https://apify.com/ntriqpro/theharvester-osint) — Emails, hosts & subdomains for a domain
- [**dnstwist-osint**](https://apify.com/ntriqpro/dnstwist-osint) — Typosquatting & phishing domain detector
- [**gitleaks-secret-scanner**](https://apify.com/ntriqpro/gitleaks-secret-scanner) — Leaked secrets in public repos
- [**maigret-actor**](https://apify.com/ntriqpro/maigret-actor) — Username OSINT across 3000+ sites

### ⭐ Love it? Leave a Review

Your rating helps other researchers discover this Actor. [Rate it here](https://apify.com/ntriqpro/subfinder-osint/reviews).

# Actor input Schema

## `domain` (type: `string`):

The root domain to enumerate subdomains for, e.g. example.com (no http://, no path).

## `maxResults` (type: `integer`):

Maximum subdomains to return and charge for (hard cap 2000).

## `timeout` (type: `integer`):

Maximum time for the enumeration.

## Actor input object example

```json
{
  "domain": "example.com",
  "maxResults": 500,
  "timeout": 180
}
```

# Actor output Schema

## `results` (type: `string`):

No description

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {
    "domain": "example.com",
    "maxResults": 500,
    "timeout": 180
};

// Run the Actor and wait for it to finish
const run = await client.actor("ntriqpro/subfinder-osint").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = {
    "domain": "example.com",
    "maxResults": 500,
    "timeout": 180,
}

# Run the Actor and wait for it to finish
run = client.actor("ntriqpro/subfinder-osint").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print("💾 Check your data here: https://console.apify.com/storage/datasets/" + run["defaultDatasetId"])
for item in client.dataset(run["defaultDatasetId"]).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{
  "domain": "example.com",
  "maxResults": 500,
  "timeout": 180
}' |
apify call ntriqpro/subfinder-osint --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "command": "npx",
            "args": [
                "mcp-remote",
                "https://mcp.apify.com/?tools=ntriqpro/subfinder-osint",
                "--header",
                "Authorization: Bearer <YOUR_API_TOKEN>"
            ]
        }
    }
}

```

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/E7YzZRDCUUXtfEii3/builds/ITPVm0W0ghrwqo0Ux/openapi.json